1. Field of the Invention
The present invention generally relates to a digital broadcasting system, and in particular, to a digital broadcasting conditional access system and method.
2. Description of the Related Art
A Conditional Access System (CAS) indicates a system for authorizing access to pay broadcasting services. A broadcasting station providing pay broadcasting services scrambles a broadcasting signal before transmission, and a receiver descrambles the received broadcasting signal, thereby allowing only an authorized subscriber to enjoy the pay broadcasting services provided.
When a broadcasting station provides free broadcasting, the CAS cannot be used. However, when such a broadcasting station requires billing for a particular reason (e.g., broadcasting subscription in shadow areas or subscription for contents requiring billing), an appropriate CAS should be implemented:
A mobile communication terminal equipped with a smart card has recently been developed and user data and other data are stored in a flash memory of the smart card. One of the representative uses of the smart card is to provide a roaming service of the mobile communication terminal with a mobile communication terminal user identity module embedded in the smart card. Examples of a mobile communication terminal user identity module include a Subscriber Identify Module (SIM) card of a Universal Mobile Telecommunication System (UMTS), a Universal Subscriber Identity Module (USIM) of a Global System for Mobile Communications (GSM) system, and a User Identity Module (UIM) card a Removal User Identity Module (RUIM) of a Code Division Multiple Access (CDMA) system and a Surface Mount Device (SMD). The smart card having the mobile communication terminal user identity module embedded therein is basically used to share data with the mobile communication terminal.
However, as a mobile communication terminal equipped with such a smart card becomes capable of receiving digital broadcasting and the demand for such an equipped mobile communication terminal increases, a digital broadcasting CAS for the mobile communication terminal is required.